1. Field of the Invention
The present invention relates in general to sports-related training and amusement devices. In particular, the present invention relates to an improved device for measuring the speed of a pitched baseball and its location within a simulated strike zone.
2. Description of the Related Art
It has been known to provide devices which will determine the location of a pitched baseball within a simulated strike zone, with certain of these devices including arrangements to determine the speed of the pitched baseball. Such devices typically take the form of a backstop having an array of pressure sensors which sense the location of the ball where it strikes the backstop. This type of pitching analyzer typically provides reduced accuracy in determining the location of the pitch within the strike zone, as the pressure sensors must be located behind a layer of padding to protect them from impact. This padding spreads the force of the impact, making it difficult to precisely determine the point of impact. Additionally, the pressure sensors are relatively expensive and are subject to failure after repeated impacts.
It is also known to form a pitching analyzer using a square or rectangular array of light beam emitters and receivers, with the light beams forming a grid. Circuitry is employed to detect those beams of light which the baseball blocks as it passes through this grid, thus determining the location of the ball within the simulated strike zone. This second arrangement provides increased reliability, but has suffered from several other drawbacks. For example, the detectors for the light beams have suffered from crosstalk from two sources.
First, ambient lighting may be sufficiently bright that the detectors do not register when the light beams have been broken. Second, the difficulty in producing a well focused light beam across the desired distances to approximate a strike zone have resulted in detectors failing to note the blockage of their associated light beam due to impingement of light from the light beams associated with adjacent ones of the detectors. To overcome this crosstalk between adjacent light beams, it has been necessary to increase the spacing between the light beams, thus reducing the 15 accuracy of detection, or to employ relatively expensive light sources to produce sufficiently tight beams. This second problem is aggravated with increased distance between the emitter and detector, causing such devices to be limited to a grid defining a simulated strike zone only, within no detection of "balls" outside the strike zone or even to a strike zone smaller than that which would be normally encountered during normal play.
Where such light grid devices have been provided with means to determine the velocity of the object passing therethrough, this has been effected by providing two parallel light grids spaced in the direction of travel of the object. The blocking of a light beam within the first grid begins a counter which is stopped upon blocking of a light beam within the second grid. The time measured by this counter is then used with the known distance between the light grids to calculate the velocity of the object. While this arrangement is sufficiently accurate, the necessity of providing two identical light grids greatly increases the cost of the device.